Transmission shift mechanism



Feb. 2, 1943. 0. FISHBIURN 2,309,837

TRANSMISSION SHIFT MECHANISM Filed Oct. 11, 1940 2 Sheets-Sheet l INVENTOR j 01% ZHlsurzz ATTORNEYS.

Feb. 2,1943. 0. E. FISHBURN 2,309,837

TRANSMISSION SHIFT MECHANISM Filed Oct. 11', 1940 2 Sheets-Shet 2 I INVENTOR. 022 0 filzzr z ATTORNEY-5.

Patented Feb. 2, 1943 TRANSMISSION SHIFT MECHA ISM Otto E. Fishburn, Detroit, Mich, assignor to Chrysler Corporation, Highland Park, Mich, a

corporation of Delaware Application October 11, 1940, Serial No. 360,733

4 Claims.

This invention relates to automobile transmission mechanism in general and particularly to improved shifting means therefor.

In transmissions of the semi-automatic type, such as that disclosed and claimed in the copending application of Carl A. Neracher et al., Serial No. 335,310, filed May 15, 1940, only three shifted positions of the hand actuated shift 1ever are provided instead of the usual four posi tions. These positions are usually arranged so that high and low range speed ratio settings may be obtained by manipulation of the lever in a lower path of movement, and reverse drive setting is obtained by movement of the lever in an upper path of movement. Because there are only two forward speed ratio settings, movement of the shift lever out of reverse position and into a forward position requires that the lever be dropped from the upper to the lower path of movement. This is disconcerting to drivers who have become accustomed to the conventional three speed and reverse shift, wherein the lowest forward speed is obtained by backward movement of the shift lever in its upper path of movem ent, and in situations where rapid shifting between reverse and forward speeds is required, difficulty is experienced because of the tendency to hold the shift lever in the upper path. If this is done, the lever will dead-end in the neutral zone and no forward speed will be obtained until the lever is dropped into its lower path of movement.

It is therefore the main object of the present invention to provide improved shifting mechanism, for transmissions of the aforesaid type whereby the above described difiiculty is eliminated and, in addition, the shift is rendered much smoother and more rapid than before.

view-taken along theline Z- 2.of Fig. 1.

thissleeve is as wil Fig. 3 is an elevational sectional view taken along the line 3 -e3 of Fig, 1.

Fig. 4. is an elevational view taken approximately alone th l e -:4 9? i Fig. 5 is a sectional view taken along the line 5.-5 of Fig. 3.

In the drawings in which reference characters are use to e i na cor esp nd ng Pa t ed to in the follow n scrip i esi H tes h ma d ve pin o f h meqhanifirh, said pinion being formed integrally at the rearward end of the input shaft H which is intended to be driven by the vehicle engine through the usual clutch mechanism inot shown). The drive pinion I 0 is hollow and journals, by a bearing I2, the forward end of the transmission'driven shaft [3 which is designed to be connected to a propeller shaft (not shown) for driving the vehicle, The drive pinion ll] is continuously meshed with a gear [6 for driving the counter- .sha t clus H w ich i a a e on Countershaft [8. The cluster 11 has a forward extension 9 i ur ahed a wit n e l6 n etween these parts I}! and L6, there is provided an overrunning clutch G. The usual speedometer drivin worm is show at 1 fixed to the s f [3 for .d ivin the usual speedometer cable,

The clutch G comprises a driving cylindrical clutching member 2! formed within gear It and an inner driven cammedmember 22 formed on extension l9. Rollers 13 are disposed between clutch memberszl an d2 2 such that these rollers are .wedged to clutch these members together when the gear It tends to rotate faster than extension IS in the forward direction of the drive of th car w i e allowing the ex ens n t freely overrun gear 16.

Ass mi he u u clockwise direction of driving shaft I I in looking f om fr nt o t e rear of t ar e l Q a es wh n a H5 t nd t ot t fa t r t an extension IS. A case 24 positions the rollers 23 in proper spa inaa s r ng 25 y el ie y u ns t ro lers in t e di ec i n o their en a ent as is customaryin ve run ine w s e The cluster IT is further formed with reduct on gears 2.6 and .2? and Y-ersaeear :23 t at i three countershaft gears heing of relatively decreasingrdiamellfir in the order mentioned. Gear 26 isinconstant mesh with the gear 29 which'is ioi rnal ed o th d i en sha t .3- Th eea pn ha a fo ward extension arr in a set" of external. driven teeth. s dabl .rlti is i ierne ui h teeth of asynchronous coupling sleeveF so that e Present mqr an aren in th transmis io dr n a ted to shaft I3 but may slide forwardly from its Fig. 2 position relatively to the driven shaft. Gear 29 has a rearward extension formed with a set of clutch teeth 36 and a friction cone clutch member 3I, and drive pinion II] also has a rearward extension formed witha set of external clutch teeth 32 and a friction cone clutch member 33.

The gear 21 is constantly meshed with a low speed gear 34 freely journalled on driven shaft I3 and having a forward extension formed with clutch teeth 35 and a cone clutch member 36. The reverse gear 28 is adapted to mesh with a reverse idler gear (not shown) when the said idler gear is shifted into mesh with the gear 39 fixed on the driven shaft I3.

The arrangement is such that shaft I3 may be selectively clutched at the will of the driver with gears 25 and 34, the control preferably com- (which operation is accomplished under synchronous control of a blocker element 48 which blocks shift of the sleeve F except when shafts,

, positions of the sleeves F and H. In the ordinary prising a manually actuated remote shift me'chanism of any suitable type and construction. The operation of the clutch sleeve F is, on the other hand, adapted to be shifted by power actuated means and is automatic in its operation of clutching driving shaft II with gear 29 for connecting these parts. The manually actuated clutching control comprises the following mechanism.

Fixed to the driven shaft I3 is a hub 40 formed with external teeth 4I slidably engaged with the internal teeth 42 of a shiftable clutch sleeve H I which is adapted for forward and rearward shift by means of a fork 43 (Figs. 1 and 3) which is fixed to a longitudinally extending shift rail 44 disposed to one side of the shaft I3 adjacent the I,

side opening 45 of casing I4.

Synchronizing blocker rings 46 and 4'! are respectively disposed between gears 23, 34 and hub 40, these rings engaging said hub with slight clearance. These blocker rings are provided with the usual cam teeth having a pitch circle the same as that of the sleeve teeth 42 and teeth respectively and they are adapted to frictionally engage the clutching members 3I and 36 respectively so that the blocker teeth are misaligned with the sleeve teeth thereby preventing shift of the clutch and rotating at different speeds. The synchronizing blocker rings are more fully described in the claims in the copending application of Otto E. Fishburn, Serial v No. 180,840, filed December 20, 1937.

When the sleeve H is moved forwardly and the teeth 4| thereof engage the cammed ends of the blocker teeth, thereby urging the blocker member under pressure engagement with cone 3I to synchronize gear 23 with shaft I3, the blocker 46 will rotate slightly relative to the hub to permit the sleeve teeth 42 to pass through the teeth of the blocker member and thereby engage the teeth 30 to positively clutch the shaft I3 with gear 29. Rearward shift of sleeve H clutches teeth 42 with teeth 35 of gear 34 and is effected in a similar manner. When the sleeve H is engaged with the clutch teeth 35, the shaft I3 is driven at the speed of the gear 34 which is in turn driven by the gear 21. The gear 21 is driven from the shaft I I at a speed ratio relative gage the teeth thereof with clutch teethv 32 formed on the rearward portion of the shaft II position.

operation of a vehicle embodying the present transmission, the operator shift sleeve H manually to obtain either low range or high range speed ratio setting thereof and sleeve F is ordinarily shifted in response to various control instrumentalities to provide high and low speed ratios for driving the vehicle when the sleeve H is positioned in either high range or low range For further details and a fuller explanation of the operation of the automatic phase of the transmission, reference is made to the aforesaid Neracher et a1. application.

The yoke 43 is provided with a boss 5I having a slot provided by lugs 50 and 52 which is adapted to be engaged by an inwardly extending shift finger 53 carried by a trunnion member 54. The trunnion member 54 is carried by a rockshaft 55 by means of a pin 56 for rocking movement about the axi of the pin which is retained in place by a clip 51. A spring 58 carried by the rockshaft 55 bears against the inner lower portion of the trunnion member 54 and biases the latter to such position that the shift finger 53 is thrust upwardly and is normally maintained in engagement with the slot between lugs 50 and 52 of yoke 43. A second yoke 59 is carried by a second shift rail 60 which is positioned directly below shift rail 44 as may be seen from Fig. 3 and engages the hub of an idler gear 6| which is adapted to be slid into mesh with the gears 28 and 39 to provide reverse drive. The yoke 59 is provided with a pair of lugs-62 and 63 which are disposed in juxtaposition relative to the lugs 56 and 52 respectively to be engaged by the shift; finger 53 upon rocking of the trunnion member 54 about the pin 56 in such manner that shift finger 53 is moved downwardly. The trunnion member 54 is rocked about the axis of the pin 56 against the force of the spring 58by means of a selector finger 64 which may be operated from the manually actuated-shift apparatus in any suitable manner, for example, by a Bowden cable or other similar means connected to a lever 64' carried by a shaft 65' as illustrated-in Fig. 1.

Rockshaft 55 is rotatably mounted in a pair of bosses 65 and 66 respectively formed in a cover member 61 which is adapted to be fastened over the opening 45 provided in the casing I4. A set screw 68 is provided for retaining the rockshaft 55 against unintentional displacement and ,a shift lever 69 is non-rotatably secured at In to the rockshaft 55 by means of a nut II. The shift lever 69 may be swung about the axis of the rockshaft 55 under the control of the manually actuated shift mechanism of the vehicle, the connection therebetween being of any suitable type.

Rocking of the rockshaft 55 with the shift finger 53 in the position shown inf Figs. 3 and 4 will cause reciprocation of the yoke 43 and shift rail 44 on which the yoke is carried to thereby engage the sleeve H with the clutch teeth-30 of gear 29 tenant or the clutchteeth 39 of the gear teeth 34 as desired. Rocking of the trunnion member 54 about the axis of the pin56 through manipulation of the selector element 64 to swing the shift finger 53 downwardly thereby to disengage the same from the slot between the lugs 59 and 52 and engage the same in the slotbetween the lugs 62 and 63 will position the mechanism for shift of the reverse idler gear 6! into mesh with gears 28 and 39 to establish reverse drive setting of the transmission. After the shift finger has been engaged in the slot between the lugs 62 and 6%, shift of the gear 61 is accomplished by clockwise rocking of the ro ckshaft 55 (as viewed in Fig. 1) through manipulation of the shift lever 68, the shift finger 53 engaging the lug 63 of yoke 59 whereby yoke 59, railfifl and gear 6| are moved 'rear'wardly.

Both rail 44 and rail 55 ar provided with depressed portions 12 which cooperate with suitable spring pressed ball detent mechanisms, one of which is shown at F3 for releasably locking the respective rails in their various operative positions. In'the embodiment of the invention described herein, the shift mechanism is designed to be used with the conventional type of steering column mounted remote shift mechanism but any other suitable type of shift mechanism may be used. When the steering column mounted type of mechanism is used, it is intended that the rocking of the trunnion member 54 b controlled by corresponding rocking movement of the manually actuated shift lever in a direction parallel to the steering column and that the swinging of the lever 69 be controlled by corresponding swinging movement of the said shift lever about the axis of the steering column or about an axis parallel to the axis of the steering column. Let

it be assumed that under such conditions, if the said manually operable shift lever is swung in a counterclockwise direction about the axis of the steering column with the shift lever positioned in its lower path of movement, which would correspond to the position of the trunnion member 54 illustrated in Fig. 3, then the rockshaft 55 will A swung in a counterclockwise direction, shift finger 53 will be engaged with yoke 59 and the said yoke 59, rail 65 and gear 6! will be shifted rearwardly to set the transmission for reverse drive.

Rail Si] is incapable of forward shifting movement from the neutral position illustrated in Fig. 4 because of the enlarged portion 14 thereof which abuts the end portion 15 of the boss 76 in which the forward ends of the rails 44 and 65 are slidably carried. Therefore, should the driver attempt to swing the manually operable shift lever out of reverse position without first returning the said lever to its low-high path of movement, the lever will stop abruptly at neutral po sition unless some means is provided for overcoming this difiiculty, which is exceedingly disconcerting to a driver accustomed to the conventional three speed and reverse'shift.

With the present improved shift mechanism,

If the manually operable shift lever is rocked upwardly and then no such abrupt stoppage of-the shift lever will occur. In Fi 4, it will be noted that the lug 50 is'considerably longer than lug 52 and lug 62 is considerably shorter than lug 63. Also lug 62 is provided with a ramp surface i1 which extends forwardly beyond the rear edge of lug 50.

It will be apparent that, with the above described arrangement, movement of the finger 53 toward the left of Fig.- 4 (by counterclockwise swinging of the rockshaft 55) with the finger 53 engaged between lugs 62 and 63 (i. e. with the manual lever in its upper path of movement) will cause yoke 43 to be shifted toward the left of Fig. 4 because lug 59 extends downwardly far enough to be engaged by finger 53 even when the latter is in its lower position. As the finger 53 is moved further toward the left, it will engage the ramp TI and will thereby be forced upwardly because of the stationary position of yoke 55. The shift of the yoke 43 will therefor be continued until high speed ratio position is reached, in which position the finger 53 will be riding on top of the lug 52. During this movement of the finger, the selector element Ki l will also be forced upwardly and this motion will be transmitted back through the shift linkage to the hand of the driver who will be apprised of the true position of the gearing.

In other words, with my improved shift mechanism, high speed ratio setting of thetransmission will be obtained whenever the rockshaft 55 is swung in a counterclockwise direction regardless of the position of the finger 53, and no shock due to abrupt stoppage of rail 63 will be felt by the driver. Furthermore, the necessity for feeling of the manual shift lever through an H-path is obviated.

Obviously, the mechanism is capable of modification to provide for a shift into low speed setting instead of high speed setting when the rockshaft is swung out of reverse setting. Such modification would require only that relative shift positions of the high-low sleeve or of the reverse gear be reversed.

Referring now to Figs. 3 and 5, it will be seen that a recess 18 is provided in the inside of the cover 6'! below the boss 65. In this recess is disposed a lever 19 which is fixed on the lower end of the rockshaft 55. The lever 79 has a wedge shaped end portion which is adapted to engage a corresponding depression in a piston 80 carried by a cylinder 8|, the latter being pivoted at 84 to the casing 82 fastened by screws 83 to the cover 61. A coil spring 85 carried in the cylinder 8| bears on the under side of the piston 80 and urges the latter against the wedge shaped end of the lever 19,

When the rockshaft 55 is rotated from neutral position in either direction, the spring urged piston 80 assists the movement thereof, the action of the spring 85 being effective as soon as the lever 19 is swung slightly out of neutral position. In other words, an over center action is imparted to the lever 12 which materially reduces the manual effort necessary to overcome the resistance encountered by the blockers t6 and 41 upon a shift in high or low range. Vfhile the action of the spring 85 tends to oppose a shift to neutral from either high or low setting, this is not a serious defect because the shift from neutral always requires more effort than the shift out of gear because of the pressure which must necessarily be applied to bring the relatively rotating members into synchronism.

It will thus be apparent that I have provided an improved shifting mechanism for transmissions of the automatic or semi-automatic type, although it is obvious that my invention is not limited in its application to the precise transmission mechanism or structure illustrated and described herein for purposes of illustrating the principles involved. Numerous changes will readily occur to those skilled in the art and I do not intend to limit the scope of invention except as set forth in the claims appended hereto.

I claim:

1. In a motor vehicle power transmission having a pair of selectively operable drive control elements, a pair of rails mounted for shiftin movement relative to each other along parallel axes, means operably connecting said rails respectively with said drive control elements, a shaft mounted for oscillatory movement about an axis transverse to said parallel axes, a selector element carried by said shaft for swinging relative thereto about an axis transverse to the axis of oscillation thereof, a shift finger carried by said element for selectively engaging said rails in response to swinging of said element, means for swinging said element, means for oscillating said shaft, a lever carried by said shaft and over center spring means associated with said lever for assisting oscillation thereof.

2. In a change speed transmission, a casing, a rockshaft, means associated with said rockshaft for effecting speed ratio changes in response to rocking thereof, a cylinder pivotally mounted in said casing, a piston in said cylinder, means for urging said piston outwardly of said cylinder, a lever carried by said rockshaft having a wedgeshaped end in engagement with said piston, said piston and lever being so disposed that said piston exerts no turning force on said rockshaft while the latter is in neutral position but is effective upon initial rocking of said shaft in either direction.

3. In a change speed transmission, a first shift yoke adapted to be shifted in opposite directions from neutral for selectively establishing apair of speed ratio drives; a second shift yoke adapted to be shifted in one direction only from neutral for establishing a third speed ratio drive; a selector and shift element adapted for movement in parallel paths for shifting said yokes; a pair of lugs on each of said yokes forming slots for receiving said element; one of the lugs on said second yoke having an inclined wall adapted for engagement by said element for camming the latter out of engagement with said second yoke and into the slot of said first yoke in response to movement of said element in a direction opposite to the shift-establishing movement thereof when engaged with said second yoke.

4. In a change speed transmission, a first shift yoke adapted to be shifted in opposite directions from neutral for selectively establishing, a pair of speed ratio drives; a second shift yoke adapted to be shifted in one direction only from neutral for establishing a third speed ratio drive; a se-- lector and shift element adapted for movement in parallel paths for shifting said yokes; a pair of lugs on each of said yokes forming slots for receiving said element; one of the lugs on said second yoke having an inclined Wall adapted for engagement by said element for camming the latter out of engagement with said second yoke and into the slot of said first yoke in response to movement of said element in a direction opposite to the shift-establishing movement thereof when engaged with said second yoke; the juxtapositioned lug of said first yoke being elongated for facilitating engagement of said element with the slot of said yoke.

OTTO E. FISHBURN. 

